docs: def _decrypt_data_key(
          self, encrypted_data_key: EncryptedDataKey, algorithm: AlgorithmSuite, encryption_context: Dict[Text, Text]
      ) -> DataKey:
          """Decrypt an encrypted data key and return the plaintext.
  
          :param data_key: Encrypted data key
          :type data_key: aws_encryption_sdk.structures.EncryptedDataKey
          :param algorithm: Algorithm object which directs how this Master Key will encrypt the data key
          :type algorithm: aws_encryption_sdk.identifiers.Algorithm
          :param dict encryption_context: Encryption context to use in decryption
          :returns: Data key containing decrypted data key
          :rtype: aws_encryption_sdk.structures.DataKey
          """
          return DataKey(
              key_provider=self.key_provider,
              data_key=self._null_plaintext_data_key(algorithm),
              encrypted_data_key=encrypted_data_key.encrypted_data_key,
          )